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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: draft-ietf-precis-framework has been published as RFC 7564 -- Possible downref: Non-RFC (?) normative reference: ref. 'UNICODE' == Outdated reference: draft-ietf-precis-mappings has been published as RFC 7790 -- Obsolete informational reference (is this intentional?): RFC 3454 (Obsoleted by RFC 7564) -- Obsolete informational reference (is this intentional?): RFC 4013 (Obsoleted by RFC 7613) Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PRECIS P. Saint-Andre 3 Internet-Draft Cisco Systems, Inc. 4 Obsoletes: 4013 (if approved) A. Melnikov 5 Intended status: Standards Track Isode Ltd 6 Expires: September 28, 2013 March 27, 2013 8 Preparation and Comparison of Internationalized Strings Representing 9 Simple User Names and Passwords 10 draft-ietf-precis-saslprepbis-01 12 Abstract 14 This document describes how to handle Unicode strings representing 15 simple user names and passwords, primarily for purposes of 16 comparison. This profile is intended to be used by Simple 17 Authentication and Security Layer (SASL) mechanisms (such as PLAIN 18 and SCRAM-SHA-1), as well as other protocols that exchange simple 19 user names or passwords. This document obsoletes RFC 4013. 21 Status of This Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at http://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on September 28, 2013. 38 Copyright Notice 40 Copyright (c) 2013 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (http://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 56 1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 2 57 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 58 2. Simple User Names . . . . . . . . . . . . . . . . . . . . . . 4 59 2.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 4 60 2.2. Preparation . . . . . . . . . . . . . . . . . . . . . . . 5 61 3. Passwords . . . . . . . . . . . . . . . . . . . . . . . . . . 5 62 3.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 5 63 3.2. Preparation . . . . . . . . . . . . . . . . . . . . . . . 6 64 4. Migration . . . . . . . . . . . . . . . . . . . . . . . . . . 6 65 4.1. User Names . . . . . . . . . . . . . . . . . . . . . . . 7 66 4.2. Passwords . . . . . . . . . . . . . . . . . . . . . . . . 8 67 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 68 5.1. Password/Passphrase Strength . . . . . . . . . . . . . . 9 69 5.2. Reuse of PRECIS . . . . . . . . . . . . . . . . . . . . . 9 70 5.3. Reuse of Unicode . . . . . . . . . . . . . . . . . . . . 9 71 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 72 6.1. Use of IdentifierClass . . . . . . . . . . . . . . . . . 9 73 6.2. Use of FreeformClass . . . . . . . . . . . . . . . . . . 10 74 7. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 10 75 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 76 8.1. Normative References . . . . . . . . . . . . . . . . . . 10 77 8.2. Informative References . . . . . . . . . . . . . . . . . 11 78 Appendix A. Differences from RFC 4013 . . . . . . . . . . . . . 12 79 Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 12 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 82 1. Introduction 84 1.1. Overview 86 User names and passwords are used pervasively in authentication and 87 authorization on the Internet. To increase the likelihood that the 88 input and comparison of user names and passwords will work in ways 89 that make sense for typical users throughout the world, this document 90 defines rules for preparing and comparing internationalized strings 91 that represent simple user names and passwords. (In many 92 authentication technologies passwords are not directly compared 93 because the actual password is used as input to an algorithm such as 94 a hash function; however, non-ASCII code points in the input string 95 still need to be handled correctly.) 96 The algorithms defined in this document assume that all strings are 97 comprised of characters from the Unicode character set [UNICODE]. 99 The algorithms are designed for use in Simple Authentication and 100 Security Layer (SASL) [RFC4422] mechanisms, such as PLAIN [RFC4616] 101 and SCRAM-SHA-1 [RFC5802]. However, they might be applicable 102 wherever simple user names or passwords are used. This profile is 103 not intended for use in preparing strings that are not simple user 104 names (e.g., email addresses, DNS domain names, LDAP distinguished 105 names), nor in cases where identifiers or secrets are not strings 106 (e.g., keys or certificates) or require different handling (e.g., 107 case folding). 109 This document builds upon the PRECIS framework defined in 110 [FRAMEWORK], which differs fundamentally from the stringprep 111 technology [RFC3454] used in SASLprep [RFC4013]. The primary 112 difference is that stringprep profiles allowed all characters except 113 those which were explicitly disallowed, whereas PRECIS profiles 114 disallow all characters except those which are explicitly allowed 115 (this "inclusion model" was originally used for internationalized 116 domain names in [RFC5891]; see [RFC5894] for further discussion). It 117 is important to keep this distinction in mind when comparing the 118 technology defined in this document to SASLprep [RFC4013]. 120 This document obsoletes RFC 4013. 122 1.2. Terminology 124 Many important terms used in this document are defined in 125 [FRAMEWORK], [RFC4422], [RFC5890], [RFC6365], and [UNICODE]. The 126 term "non-ASCII space" refers to any Unicode code point with a 127 general category of "Zs", with the exception of U+0020 (here called 128 "ASCII space"). 130 As used here, the term "password" is not literally limited to a word; 131 i.e., a password could be a passphrase consisting of more than one 132 word, perhaps separated by spaces or other such characters. 134 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 135 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 136 "OPTIONAL" in this document are to be interpreted as described in 137 [RFC2119]. 139 2. Simple User Names 141 2.1. Definition 143 Some SASL mechanisms (e.g., CRAM-MD5, DIGEST-MD5, and SCRAM) specify 144 that the authentication identity used in the context of such 145 mechanisms is a "simple user name" (see Section 2 of [RFC4422] as 146 well as [RFC4013]). However, the exact form of a simple user name in 147 any particular mechanism or deployment thereof is a local matter, and 148 a simple user name does not necessarily map to an application 149 identifier such as the localpart of an email address. 151 For purposes of preparation and comparison of authentication 152 identities, this document specifies that a simple user name is a 153 string of Unicode code points [UNICODE], encoded using UTF-8 154 [RFC3629], and structured either as an ordered sequence of 155 "simpleparts" (where the complete simple user name can consist of a 156 single simplepart or a space-separated sequence of simpleparts) or as 157 a simplepart@domainpart (where the domainpart is an IP literal, an 158 IPv4 address, or a fully-qualified domain name). 160 Therefore the syntax for a simple user name is defined as follows 161 using the Augmented Backus-Naur Form (ABNF) as specified in 162 [RFC5234]. 164 simpleusername = simplepart [1*(1*SP simplepart)] 165 / simplepart '@' domainpart 166 simplepart = 1*(idpoint) 167 ; 168 ; an "idpoint" is a UTF-8 encoded 169 ; Unicode code point that conforms to 170 ; the PRECIS "IdentifierClass" 171 ; 172 domainpart = IP-literal / IPv4address / ifqdn 173 ; 174 ; the "IPv4address" and "IP-literal" 175 ; rules are defined in RFC 3986, and 176 ; the first-match-wins (a.k.a. "greedy") 177 ; algorithm described in RFC 3986 178 ; applies to the matching process 179 ; 180 ; note well that reuse of the IP-literal 181 ; rule from RFC 3986 implies that IPv6 182 ; addresses are enclosed in square 183 ; brackets (i.e., beginning with '[' 184 ; and ending with ']') 185 ; 186 ifqdn = 1*1023(domainpoint) 187 ; 188 ; a "domainpoint" is a UTF-8 encoded 189 ; Unicode code point that conforms to 190 ; RFC 5890 191 ; 193 Note well that all code points and blocks not explicitly allowed in 194 the PRECIS IdentifierClass are disallowed; this includes private use 195 characters, surrogate code points, and the other code points and 196 blocks defined as "Prohibited Output" in Section 2.3 of RFC 4013. 198 Note also that common constructions such as "user@example.com" are 199 allowed as simple user names when using software that conforms to 200 this specification, as they were under [RFC4013]. 202 2.2. Preparation 204 A simple user name MUST NOT be zero bytes in length. This rule is to 205 be enforced after any normalization and mapping of code points. 207 Each simplepart of a simple user name MUST conform to the definition 208 of the PRECIS IdentifierClass provided in [FRAMEWORK], where the 209 normalization, casemapping, and directionality rules are as described 210 below. 212 1. Unicode Normalization Form C (NFC) MUST be applied to all 213 characters. 215 2. Uppercase and titlecase characters MUST be mapped to their 216 lowercase equivalents. 218 3. Additional mappings MAY be applied, such as those defined in 219 [I-D.ietf-precis-mappings]. 221 With regard to directionality, the "Bidi Rule" provided in [RFC5893] 222 applies. 224 3. Passwords 226 3.1. Definition 228 For purposes of preparation and comparison of passwords, this 229 document specifies that a password is a string of Unicode code points 230 [UNICODE], encoded using UTF-8 [RFC3629], and conformant to the 231 PRECIS FreeformClass. 233 Therefore the syntax for a password is defined as follows using the 234 Augmented Backus-Naur Form (ABNF) as specified in [RFC5234]. 236 password = 1*(freepoint) 237 ; 238 ; a "freepoint" is a UTF-8 encoded 239 ; Unicode code point that conforms to 240 ; the PRECIS "FreeformClass" 241 ; 243 Note well that all code points and blocks not explicitly allowed in 244 the PRECIS FreeformClass are disallowed; this includes private use 245 characters, surrogate code points, and the other code points and 246 blocks defined as "Prohibited Output" in Section 2.3 of RFC 4013. 248 3.2. Preparation 250 A password MUST NOT be zero bytes in length. This rule is to be 251 enforced after any normalization and mapping of code points. 253 A password MUST be treated as follows, where the operations specified 254 MUST be completed in the order shown: 256 1. Apply Unicode Normalization Form C (NFC) to all characters. 258 2. Map any instances of non-ASCII space to ASCII space (U+0020). 260 3. Ensure that the resulting string conforms to the definition of 261 the PRECIS FreeformClass. 263 With regard to directionality, the "Bidi Rule" (defined in [RFC5893]) 264 and similar rules are unnecessary and inapplicable to passwords, 265 since they can reduce the range of characters that are allowed in a 266 string and therefore reduce the amount of entropy that is possible in 267 a password. Furthermore, such rules are intended to minimize the 268 possibility that the same string will be displayed differently on a 269 system set for right-to-left display and a system set for left-to- 270 right display; however, passwords are typically not displayed at all 271 and are rarely meant to be interoperable across different systems in 272 the way that non-secret strings like domain names and user names are. 274 4. Migration 276 The rules defined in this specification differ slightly from those 277 defined by the SASLprep specification [RFC4013]. The following 278 sections describe these differences, along with their implications 279 for migration, in more detail. 281 4.1. User Names 283 Deployments that currently use SASLprep for handling user names might 284 need to scrub existing data when migrating to use of the rules 285 defined in this specification. In particular: 287 o SASLprep specified the use of Unicode Normalization Form KC 288 (NFKC), whereas this usage of the PRECIS IdentifierClass employs 289 Unicode Normalization Form C (NFC). In practice this change is 290 unlikely to cause significant problems, because NFKC provides 291 methods for mapping Unicode code points with compatibility 292 equivalents to those equivalents, whereas the PRECIS 293 IdentifierClass entirely disallows Unicode code points with 294 compatibility equivalents (i.e., during comparison NFKC is more 295 "aggressive" about finding matches than is NFC). A few examples 296 might suffice to indicate the nature of the problem: (1) U+017F 297 LATIN SMALL LETTER LONG S is compatibility equivalent to U+0073 298 LATIN SMALL LETTER S (2) U+2163 ROMAN NUMERAL FOUR is 299 compatibility equivalent to U+0049 LATIN CAPITAL LETTER I and 300 U+0056 LATIN CAPITAL LETTER V (3) U+FB01 LATIN SMALL LIGATURE FI 301 is compatibility equivalent to U+0066 LATIN SMALL LETTER F and 302 U+0069 LATIN SMALL LETTER I. Under SASLprep, the use of NFKC also 303 handled the mapping of fullwidth and halfwidth code points to 304 their decomposition equivalents (see [I-D.ietf-precis-mappings]). 305 Although it is expected that code points with compatibility 306 equivalents are rare in existing user names, for migration 307 purposes deployments might want to search their database of user 308 names for Unicode code points with compatibility equivalents and 309 map those code points to their compatibility equivalents. 311 o SASLprep mapped non-ASCII spaces to ASCII space (U+0020), whereas 312 the PRECIS IdentifierClass entirely disallows non-ASCII spaces. 313 The non-ASCII space characters are U+00A0 NO-BREAK SPACE, U+1680 314 OGHAM SPACE MARK, U+180E MONGOLIAN VOWEL SEPARATOR, U+2000 EN QUAD 315 through U+200A HAIR SPACE, U+202F NARROW NO-BREAK SPACE, U+205F 316 MEDIUM MATHEMATICAL SPACE, and U+3000 IDEOGRAPHIC SPACE. For 317 migration purposes, deployments might want to convert non-ASCII 318 space characters to ASCII space in simple user names. 320 o SASLprep mapped the "characters commonly mapped to nothing" from 321 Appendix B.1 of [RFC3454]) to nothing, whereas the PRECIS 322 IdentifierClass entirely disallows most of these characters, which 323 correspond to the code points from the "M" category defined under 324 Section 6.13 of [FRAMEWORK] (with the exception of U+1806 325 MONGOLIAN TODO SOFT HYPHEN, which was "commonly mapped to nothing" 326 in Unicode 3.2 but at the time of this writing does not have a 327 derived property of Default_Ignorable_Code_Point in Unicode 6.1). 328 For migration purposes, deployments might want to remove code 329 points contained in the PRECIS "M" category from simple user 330 names. 332 o SASLprep allowed uppercase and titlecase characters, whereas this 333 usage of the PRECIS IdentifierClass maps uppercase and titlecase 334 characters to their lowercase equivalents. For migration 335 purposes, deployments can either convert uppercase and titlecase 336 characters to their lowercase equivalents in simple user names 337 (thus losing the case information) or preserve uppercase and 338 titlecase characters and ignore the case difference when comparing 339 simple user names. 341 4.2. Passwords 343 Depending on local service policy, migration from RFC 4013 to this 344 specification might not involve any scrubbing of data (since 345 passwords might not be stored in the clear anyway); however, service 346 providers need to be aware of possible issues that might arise during 347 migration. In particular: 349 o SASLprep specified the use of Unicode Normalization Form KC 350 (NFKC), whereas this usage of the PRECIS FreeformClass employs 351 Unicode Normalization Form C (NFC). Because NFKC is more 352 aggressive about finding matches than NFC, in practice this change 353 is unlikely to cause significant problems and indeed has the 354 security benefit of probably resulting in fewer false positives 355 when comparing passwords. A few examples might suffice to 356 indicate the nature of the problem: (1) U+017F LATIN SMALL LETTER 357 LONG S is compatibility equivalent to U+0073 LATIN SMALL LETTER S 358 (2) U+2163 ROMAN NUMERAL FOUR is compatibility equivalent to 359 U+0049 LATIN CAPITAL LETTER I and U+0056 LATIN CAPITAL LETTER V 360 (3) U+FB01 LATIN SMALL LIGATURE FI is compatibility equivalent to 361 U+0066 LATIN SMALL LETTER F and U+0069 LATIN SMALL LETTER I. 362 Under SASLprep, the use of NFKC also handled the mapping of 363 fullwidth and halfwidth code points to their decomposition 364 equivalents (see [I-D.ietf-precis-mappings]). Although it is 365 expected that code points with compatibility equivalents are rare 366 in existing passwords, some passwords that matched when SASLprep 367 was used might no longer work when the rules in this specification 368 are applied. 370 o SASLprep mapped the "characters commonly mapped to nothing" from 371 Appendix B.1 of [RFC3454]) to nothing, whereas the PRECIS 372 FreeformClass entirely disallows such characters, which correspond 373 to the code points from the "M" category defined under 374 Section 6.13 of [FRAMEWORK] (with the exception of U+1806 375 MONGOLIAN TODO SOFT HYPHEN, which was commonly mapped to nothing 376 in Unicode 3.2 but at the time of this writing is allowed by 377 Unicode 6.1). In practice, this change will probably have no 378 effect on comparison, but user-oriented software might reject such 379 code points instead of ignoring them during password preparation. 381 5. Security Considerations 383 5.1. Password/Passphrase Strength 385 The ability to include a wide range of characters in passwords and 386 passphrases can increase the potential for creating a strong password 387 with high entropy. However, in practice, the ability to include such 388 characters ought to be weighed against the possible need to reproduce 389 them on various devices using various input methods. 391 5.2. Reuse of PRECIS 393 The security considerations described in [FRAMEWORK] apply to the 394 "IdentifierClass" and "FreeformClass" base string classes used in 395 this document for simple user names and passwords, respectively. 397 5.3. Reuse of Unicode 399 The security considerations described in [UTR39] apply to the use of 400 Unicode characters in user names and passwords. 402 6. IANA Considerations 404 6.1. Use of IdentifierClass 406 The IANA shall add an entry to the PRECIS Usage Registry for reuse of 407 the PRECIS IdentifierClass in SASL, as follows: 409 Applicability: Usernames in SASL and Kerberos. 411 Base Class: IdentifierClass. 413 Subclass: No. 415 Replaces: The SASLprep profile of Stringprep. 417 Normalization: NFC. 419 Casemapping: Map uppercase and titlecase characters to lowercase. 421 Additional Mappings: None. 423 Directionality: The "Bidi Rule" defined in RFC 5893 applies. 425 Specification: RFC XXXX. [Note to RFC Editor: please change XXXX to 426 the number issued for this specification.] 428 6.2. Use of FreeformClass 430 The IANA shall add an entry to the PRECIS Usage Registry for reuse of 431 the PRECIS FreeformClass in SASL, as follows: 433 Applicability: Passwords in SASL and Kerberos. 435 Base Class: FreeformClass 437 Subclass: No. 439 Replaces: The SASLprep profile of Stringprep. 441 Normalization: NFC. 443 Casemapping: None. 445 Additional Mappings: Map non-ASCII space characters to ASCII space. 447 Directionality: None. 449 Specification: RFC XXXX. [Note to RFC Editor: please change XXXX to 450 the number issued for this specification.] 452 7. Open Issues 454 We need to compare the output obtained when applying the new rules 455 with Unicode 3.2 and Unicode 6.1 data to the output obtained when 456 applying the SASLprep rules with Unicode 3.2 data, then make sure 457 that the PRECIS Working Group and KITTEN Working Group are 458 comfortable with any changes to the Unicode characters that are 459 allowed and disallowed. (See also the migration issues described 460 under Section 4.) 462 8. References 464 8.1. Normative References 466 [FRAMEWORK] 467 Saint-Andre, P. and M. Blanchet, "Precis Framework: 468 Handling Internationalized Strings in Protocols", draft- 469 ietf-precis-framework-07 (work in progress), March 2013. 471 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 472 Requirement Levels", BCP 14, RFC 2119, March 1997. 474 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 475 10646", STD 63, RFC 3629, November 2003. 477 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 478 Specifications: ABNF", STD 68, RFC 5234, January 2008. 480 [UNICODE] The Unicode Consortium, "The Unicode Standard, Version 481 6.1", 2012, 482 . 484 8.2. Informative References 486 [I-D.ietf-precis-mappings] 487 YONEYA, Y. and T. NEMOTO, "Mapping characters for PRECIS 488 classes", draft-ietf-precis-mappings-01 (work in 489 progress), December 2012. 491 [RFC3454] Hoffman, P. and M. Blanchet, "Preparation of 492 Internationalized Strings ("stringprep")", RFC 3454, 493 December 2002. 495 [RFC4013] Zeilenga, K., "SASLprep: Stringprep Profile for User Names 496 and Passwords", RFC 4013, February 2005. 498 [RFC4422] Melnikov, A., Ed. and K. Zeilenga, Ed., "Simple 499 Authentication and Security Layer (SASL)", RFC 4422, June 500 2006. 502 [RFC4616] Zeilenga, K., "The PLAIN Simple Authentication and 503 Security Layer (SASL) Mechanism", RFC 4616, August 2006. 505 [RFC5802] Newman, C., Menon-Sen, A., Melnikov, A., and N. Williams, 506 "Salted Challenge Response Authentication Mechanism 507 (SCRAM) SASL and GSS-API Mechanisms", RFC 5802, July 2010. 509 [RFC5890] Klensin, J., "Internationalized Domain Names for 510 Applications (IDNA): Definitions and Document Framework", 511 RFC 5890, August 2010. 513 [RFC5891] Klensin, J., "Internationalized Domain Names in 514 Applications (IDNA): Protocol", RFC 5891, August 2010. 516 [RFC5893] Alvestrand, H. and C. Karp, "Right-to-Left Scripts for 517 Internationalized Domain Names for Applications (IDNA)", 518 RFC 5893, August 2010. 520 [RFC5894] Klensin, J., "Internationalized Domain Names for 521 Applications (IDNA): Background, Explanation, and 522 Rationale", RFC 5894, August 2010. 524 [RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in 525 Internationalization in the IETF", BCP 166, RFC 6365, 526 September 2011. 528 [UTR39] The Unicode Consortium, "Unicode Technical Report #39: 529 Unicode Security Mechanisms", August 2010, 530 . 532 Appendix A. Differences from RFC 4013 534 The following substantive modifications were made from RFC 4013. 536 o A single SASLprep algorithm was replaced by two separate 537 algorithms: one for simple user names and another for passwords. 539 o The new preparation algorithms use PRECIS instead of a stringprep 540 profile. The new algorithms work independenctly of Unicode 541 versions. 543 o As recommended in the PRECIS framwork, changed the Unicode 544 normalization form from NFKC to NFC. 546 o Some Unicode code points that were mapped to nothing in RFC 4013 547 are simply disallowed by PRECIS. 549 Appendix B. Acknowledgements 551 Thanks to Yoshiro YONEYA and Takahiro NEMOTO for implementation 552 feedback. Thanks also to Marc Blanchet, Joe Hildebrand, Alan DeKok, 553 Simon Josefsson, Jonathan Lennox, Matt Miller, Chris Newman, Pete 554 Resnick, Andrew Sullivan, and Nico Williams for their input. 556 This document borrows some text from RFC 4013 and RFC 6120. 558 Authors' Addresses 560 Peter Saint-Andre 561 Cisco Systems, Inc. 562 1899 Wynkoop Street, Suite 600 563 Denver, CO 80202 564 USA 566 Phone: +1-303-308-3282 567 Email: psaintan@cisco.com 568 Alexey Melnikov 569 Isode Ltd 570 5 Castle Business Village 571 36 Station Road 572 Hampton, Middlesex TW12 2BX 573 UK 575 Email: Alexey.Melnikov@isode.com